Journal Article10.1111/GFL.12083
Changes in fluid pathways in a calcite vein mesh (Natih Formation, Oman Mountains) : insights from stable isotopes
TL;DR: In this article, a structural, microstructural, and stable isotope study of a calcite vein mesh within the Cretaceous Natih Formation in the Oman Mountains is presented to explore changes in fluid pathways during vein formation.
read more
Abstract: We present a structural, microstructural, and stable isotope study of a calcite vein mesh within the Cretaceous Natih Formation in the Oman Mountains to explore changes in fluid pathways during vein formation. Stage 1 veins form a mesh of steeply dipping crack-seal extension veins confined to a 3.5-m-thick stratigraphic interval. Different strike orientations of Stage 1 veins show mutually crosscutting relationships. Stage 2 veins occur in the dilatant parts of a younger normal fault interpreted to penetrate the stratigraphy below. The δ18O composition of the host rock ranges from 21.8‰ to 23.7‰. The δ13C composition ranges from 1.5‰ to 2.3‰. This range is consistent with regionally developed diagenetic alteration at top of the Natih Formation. The δ18O composition of vein calcite varies from 22.5‰ to 26.2‰, whereas δ13C composition ranges from −0.8‰ to 2.1‰. A first trend observed in Stage 1 veins involves a decrease of δ13C to compositions nearly 1.3‰ lower than the host rock, whereas δ18O remains constant. A second trend observed in Stage 2 calcite has δ18O values up to 3.3‰ higher than the host rock, whereas the δ13C composition is similar. Stable isotope data and microstructures indicate an episodic flow regime for both stages. During Stage 1, formation of a stratabound vein mesh involved bedding-parallel flow, under near-lithostatic fluid pressures. The 18O fluid composition was host rock-buffered, whereas 13C composition was relatively depleted. This may reflect reaction of low 13C CO2 derived by fluid interaction with organic matter in the limestones. Stage 2 vein formation is associated with fault-controlled fluid flow accessing fluids in equilibrium with limestones about 50 m beneath. We highlight how evolution of effective stress states and the growth of faults influence the hydraulic connectivity in fracture networks and we demonstrate the value of stable isotopes in tracking changes in fluid pathways.
read more
Chat with Paper
AI Agents for this Paper
Find similar papers on Google Scholar, PubMed and Arxiv
Write a critical review of this paper
Analyze citations of this paper to find unaddressed research gaps
Citations
Relationships between fractures
TL;DR: Fracture interactions are characterised in terms of the following as mentioned in this paper : 1) Fracture type: whether they have opening (e.g., joints, veins, dykes), closing (stylolites, compaction bands), or mixed-mode displacements.
110
Microfracture spacing distributions and the evolution of fracture patterns in sandstones
TL;DR: In this article, the authors reconstructed the opening history of a cluster of fractures within the Huizachal Group in northeastern Mexico, using fluid inclusions from synkinematic cements and thermal-history constraints.
71
Tectono-thermal evolution of Oman's Mesozoic passive continental margin under the obducting Semail Ophiolite: a case study of Jebel Akhdar, Oman
Arne Steffen Grobe,Christoph von Hagke,Ralf Littke,István Dunkl,F. Wübbeler,Philippe Muchez,János Urai,János Urai +7 more
TL;DR: In this article, a study of pressure and temperature evolution in the passive continental margin under the Oman Ophiolite using numerical basin models is presented, calibrated with thermal maturity data, fluid-inclusion thermometry, and low-temperature thermochronometry.
Chemostratigraphy of the Upper Albian to mid‐Turonian Natih Formation (Oman) – how authigenic carbonate changes a global pattern
Stephan Wohlwend,Malcolm B. Hart,Helmut Weissert +2 more
- 01 May 2016
TL;DR: In this paper, the authors established a biostratigraphy and chemostratigy of the Natih Formation and reconstructed depositional conditions of organic-rich sediments in an intra-platform basin during Cenomanian-Turonian times.
49
Multiphase Structural Evolution of a Continental Margin During Obduction Orogeny: Insights From the Jebel Akhdar Dome, Oman Mountains
TL;DR: In this article, the authors present an extensive structural analysis of the Jebel Akhdar anticline, the largest tectonic window of the Oman Mountains and integrate it on different scales.
47
References
The transition from a passive margin to an Upper Cretaceous foreland basin related to ophiolite emplacement in the Oman Mountains
TL;DR: In this paper, the authors show that the upper Cretaceous Muti Formation in the Oman Mountains exemplifies the transition from a passive continental margin to a foreland basin related to thrusting and ophiolite emplacement.
161
Late Cretaceous to Paleogene post-obduction extension and subsequent Neogene compression in the Oman Mountains
TL;DR: A tectonic survey, based on structural analysis of faultslip data in the post-nappe units of the Oman Mountains, allowed the authors of as mentioned in this paper to identify major events of the Late Cretaceous and Cenozoic Tectonic history of northern Oman.
Focused fluid flow along faults in the Monterey Formation, coastal California
Peter Eichhubl,James R. Boles +1 more
TL;DR: In this paper, a mass-balance estimate of the fluid volume required for fault cementation at Jalama Beach is derived based on strontium isotopic composition of carbonate fault cement, and the minimum distance of formation-parallel flow into the fault zone is 4 km and possibly > 12 km.